Pulmonary hypertension turns up in nearly a third of sleep apnoea patients

Obstructive sleep apnoea, where the airway repeatedly collapses during sleep, is common and increasingly diagnosed, and its links to daytime fatigue and high blood pressure are well known. Less appreciated is pulmonary hypertension, a serious cardiovascular complication in which pressure rises in the arteries supplying the lungs. How often the two conditions coexist, and whether more severe apnoea means more pulmonary hypertension, had not been clearly quantified. This meta-analysis set out to pool the available studies and answer both questions.

The authors searched the literature on 13 May 2025 for studies reporting the prevalence of pulmonary hypertension in people with obstructive sleep apnoea, or comparing apnoea patients with and without it. From 4,852 records, 53 studies entered the review and 46 the pooled analysis, together covering 1,190 apnoea patients with pulmonary hypertension and 2,967 without. Analyses were broken down by apnoea severity thresholds, by how pulmonary hypertension was diagnosed, and by study design, with sensitivity checks excluding small samples and retrospective studies.

Using the standard diagnostic threshold for apnoea, the pooled prevalence of pulmonary hypertension was 29.3%, and the estimate stayed similar when restricted to studies using right heart catheterisation (29.6%), the reference diagnostic method, or when excluding small samples (30.9%) or retrospective designs (30.3%). Strikingly, prevalence did not differ significantly between mild-to-moderate and severe apnoea. Patients with both conditions did have higher body mass index, more breathing interruptions per hour, more frequent oxygen dips and lower average overnight oxygen than those with apnoea alone, while age and sex made no difference. Estimates varied enormously between the pooled studies.

A prevalence near 29-31% is higher than many would assume, and the finding that severity categories did not track pulmonary hypertension complicates the intuition that only severe apnoea threatens the heart and lungs. The pooled studies came largely from clinical settings, where patients tend to be sicker than the wider population of people with apnoea, so the true community rate is probably lower. The enormous variation between studies also means the headline figure is an approximation. What the analysis does suggest is that worse overnight oxygenation, more than the severity label itself, marks those affected.

For anyone with diagnosed or suspected sleep apnoea, this is a reason to take the condition's cardiovascular dimension seriously regardless of whether it was labelled mild, moderate or severe, since the severity category did not predict pulmonary hypertension here. The markers that did travel with the complication were higher body weight and worse overnight oxygen levels. This is information about how common the overlap was in studied patients, not a reason for alarm: the samples skew towards clinic populations, and the analysis says nothing about any individual's risk.